======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:5/144 is trying to acquire lock:
ffff88807998f5f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xff/0x1380 fs/hfs/extent.c:397

but task is already holding lock:
ffff88801ef4e0b0 (&tree->tree_lock#2/1){+.+.}-{3:3}, at: hfs_find_init+0x17e/0x1f0 fs/hfs/bfind.c:-1

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock#2/1){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
       hfs_find_init+0x17e/0x1f0 fs/hfs/bfind.c:-1
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_extend_file+0x361/0x1380 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
       hfs_cat_create+0x1fe/0x6b0 fs/hfs/catalog.c:104
       hfs_mkdir+0x6c/0xe0 fs/hfs/dir.c:232
       vfs_mkdir+0x296/0x440 fs/namei.c:4121
       do_mkdirat+0x1dc/0x450 fs/namei.c:4144
       __do_sys_mkdirat fs/namei.c:4159 [inline]
       __se_sys_mkdirat fs/namei.c:4157 [inline]
       __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4157
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
       hfs_extend_file+0xff/0x1380 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
       __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
       hfs_ext_write_extent+0x17f/0x210 fs/hfs/extent.c:144
       hfs_write_inode+0xdc/0x880 fs/hfs/inode.c:434
       write_inode fs/fs-writeback.c:1483 [inline]
       __writeback_single_inode+0x705/0xec0 fs/fs-writeback.c:1700
       writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926
       wb_writeback+0x46a/0xbf0 fs/fs-writeback.c:2105
       wb_do_writeback fs/fs-writeback.c:2252 [inline]
       wb_workfn+0x400/0xe60 fs/fs-writeback.c:2292
       process_one_work kernel/workqueue.c:2653 [inline]
       process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
       worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
       kthread+0x2fa/0x390 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tree->tree_lock#2/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock#2/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

3 locks held by kworker/u4:5/144:
 #0: ffff88801ce7b138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #0: ffff88801ce7b138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #1: ffffc90002dc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #1: ffffc90002dc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #2: ffff88801ef4e0b0 (&tree->tree_lock#2/1){+.+.}-{3:3}, at: hfs_find_init+0x17e/0x1f0 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 0 PID: 144 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
 hfs_extend_file+0xff/0x1380 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
 hfs_ext_write_extent+0x17f/0x210 fs/hfs/extent.c:144
 hfs_write_inode+0xdc/0x880 fs/hfs/inode.c:434
 write_inode fs/fs-writeback.c:1483 [inline]
 __writeback_single_inode+0x705/0xec0 fs/fs-writeback.c:1700
 writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926
 wb_writeback+0x46a/0xbf0 fs/fs-writeback.c:2105
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0x400/0xe60 fs/fs-writeback.c:2292
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
hfs: new node 0 already hashed?
------------[ cut here ]------------
WARNING: CPU: 1 PID: 144 at fs/hfs/bnode.c:520 hfs_bnode_create+0x3b9/0x440 fs/hfs/bnode.c:519
Modules linked in:
CPU: 1 PID: 144 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: writeback wb_workfn (flush-7:4)
RIP: 0010:hfs_bnode_create+0x3b9/0x440 fs/hfs/bnode.c:520
Code: d4 e0 8a 89 ee e8 47 8c 1f 08 e9 73 fd ff ff e8 1d 1c 2d ff 4c 89 ef e8 45 bc 34 08 48 c7 c7 c0 d4 e0 8a 89 ee e8 27 8c 1f 08 <0f> 0b eb b7 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 7f fc ff ff 4c
RSP: 0018:ffffc90002dc6e18 EFLAGS: 00010246
RAX: 000000000000001f RBX: ffff88801ef4e000 RCX: 082a14c60fc0dc00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffc90002dc6a27 R09: 1ffff920005b8d44
R10: dffffc0000000000 R11: fffff520005b8d45 R12: 0000000000000000
R13: ffff88801ef4e0e0 R14: ffff88802f22db00 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d921ff8 CR3: 0000000074e01000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 hfs_bmap_alloc+0x541/0x5d0 fs/hfs/btree.c:326
 hfs_btree_inc_height+0x101/0xac0 fs/hfs/brec.c:490
 hfs_brec_insert+0x748/0xbd0 fs/hfs/brec.c:148
 __hfs_ext_write_extent+0x2a1/0x470 fs/hfs/extent.c:124
 hfs_ext_write_extent+0x17f/0x210 fs/hfs/extent.c:144
 hfs_write_inode+0xdc/0x880 fs/hfs/inode.c:434
 write_inode fs/fs-writeback.c:1483 [inline]
 __writeback_single_inode+0x705/0xec0 fs/fs-writeback.c:1700
 writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926
 wb_writeback+0x46a/0xbf0 fs/fs-writeback.c:2105
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0x400/0xe60 fs/fs-writeback.c:2292
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>